TY - JOUR
T1 - CO J = 2-1 line emission in cluster galaxies at z ̃ 1
T2 - Fueling star formation in dense environments
AU - Wagg, Jeff
AU - Pope, Alexandra
AU - Alberts, Stacey
AU - Armus, Lee
AU - Brodwin, Mark
AU - Bussmann, Robert S.
AU - Desai, Vandana
AU - Dey, Arjun
AU - Jannuzi, Buell
AU - Le Floc'H, Emeric
AU - Melbourne, Jason
AU - Stern, Daniel
PY - 2012/6/20
Y1 - 2012/6/20
N2 - We present observations of CO J = 2-1 line emission in infrared-luminous cluster galaxies at z 1 using the IRAM Plateau de Bure Interferometer. Our two primary targets are optically faint, dust-obscured galaxies (DOGs) found to lie within 2Mpc of the centers of two massive (>1014 M) galaxy clusters. CO line emission is not detected in either DOG. We calculate 3σ upper limits to the CO J = 2-1 line luminosities, L′CO < 6.08 × 109 and <6.63 × 109 Kkms -1pc2. Assuming a CO-to-H2 conversion factor derived for ultraluminous infrared galaxies in the local universe, this translates to limits on the cold molecular gas mass of and . Both DOGs exhibit mid-infrared continuum emission that follows a power law, suggesting that an active galactic nucleus (AGN) contributes to the dust heating. As such, estimates of the star formation efficiencies in these DOGs are uncertain. A third cluster member with an infrared luminosity, L IR < 7.4 × 1011 L, is serendipitously detected in CO J = 2-1 line emission in the field of one of the DOGs located roughly two virial radii away from the cluster center. The optical spectrum of this object suggests that it is likely an obscured AGN, and the measured CO line luminosity is L′CO = (1.94 ± 0.35) × 1010 Kkms -1pc2, which leads to an estimated cold molecular gas mass . A significant reservoir of molecular gas in a z 1 galaxy located away from the cluster center demonstrates that the fuel can exist to drive an increase in star formation and AGN activity at the outskirts of high-redshift clusters.
AB - We present observations of CO J = 2-1 line emission in infrared-luminous cluster galaxies at z 1 using the IRAM Plateau de Bure Interferometer. Our two primary targets are optically faint, dust-obscured galaxies (DOGs) found to lie within 2Mpc of the centers of two massive (>1014 M) galaxy clusters. CO line emission is not detected in either DOG. We calculate 3σ upper limits to the CO J = 2-1 line luminosities, L′CO < 6.08 × 109 and <6.63 × 109 Kkms -1pc2. Assuming a CO-to-H2 conversion factor derived for ultraluminous infrared galaxies in the local universe, this translates to limits on the cold molecular gas mass of and . Both DOGs exhibit mid-infrared continuum emission that follows a power law, suggesting that an active galactic nucleus (AGN) contributes to the dust heating. As such, estimates of the star formation efficiencies in these DOGs are uncertain. A third cluster member with an infrared luminosity, L IR < 7.4 × 1011 L, is serendipitously detected in CO J = 2-1 line emission in the field of one of the DOGs located roughly two virial radii away from the cluster center. The optical spectrum of this object suggests that it is likely an obscured AGN, and the measured CO line luminosity is L′CO = (1.94 ± 0.35) × 1010 Kkms -1pc2, which leads to an estimated cold molecular gas mass . A significant reservoir of molecular gas in a z 1 galaxy located away from the cluster center demonstrates that the fuel can exist to drive an increase in star formation and AGN activity at the outskirts of high-redshift clusters.
KW - ISM: molecules
KW - galaxies: clusters: general
KW - galaxies: evolution
KW - galaxies: formation
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U2 - 10.1088/0004-637X/752/2/91
DO - 10.1088/0004-637X/752/2/91
M3 - Article
AN - SCOPUS:84861897447
SN - 0004-637X
VL - 752
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 91
ER -